diff --git a/libguile/strings.c b/libguile/strings.c
index 24c82fc..dd70ce1 100644
--- a/libguile/strings.c
+++ b/libguile/strings.c
@@ -1779,14 +1779,15 @@ scm_to_latin1_stringn (SCM str, size_t *lenp)
 
   if (scm_i_is_narrow_string (str))
     {
+      size_t len = scm_i_string_length (str);
       if (lenp)
-	*lenp = scm_i_string_length (str);
-
-      result = scm_strdup (scm_i_string_data (str));
+        *lenp = len;
+      result = scm_strndup (scm_i_string_data (str), len);
     }
   else
     result = scm_to_stringn (str, lenp, NULL,
-			     SCM_FAILED_CONVERSION_ERROR);
+                             SCM_FAILED_CONVERSION_ERROR);
+}
 
   return result;
 }